What goes up, comes down.

Shares of Weight Watchers fell nearly 5 percent, to $88, in after-hours trading after the dieting company said it didn’t sign up as many new subscribers in the second quarter as it did in the first.

While Weight Watchers added 1 million new members compared with a year ago, bringing the total to 4.5 million, it was still fewer than the 4.6 million signed up in the quarter ended in March.

“Broadly speaking, I see the 18 percent revenue growth from a year ago” to $410 million, said Chief Financial Officer Nicholas Hotchkin during an earnings call with analysts. “I don’t see the business slowing but accelerating,” he added.

Investors also questioned the company’s decision not to buy television advertising during the fall — as it has in the past — and to rely more heavily on digital videos.

Still, management said the company is attracting a broader and more diverse customer base, including new dads and is also retaining customers longer, more than nine months.

It’s tapping a growing number of social media influencers, including hip-hop producer DJ Khaled, to help recruit members.

A new loyalty program will be launched in the coming months, said CEO Mindy Grossman, explaining that members will get points for health behaviors rather than for their spending.

“Healthy is the new skinny,” Grossman said, quoting Weight Watchers celebrity investor Oprah Winfrey.